Safety device for burners and the like



J. A. SPENCER Filed June 17, 1930 Dec. 11, 1934.

SAFETY DEVICE FOR BURNERS AND THE LIKE" Patented Dec. 11, 1934 UNITED STATES SAFETY DEVICE FOR BURNERS AND THE LIKE John A. Spencer, Newton, Masa, assignor to The Spencer Thermostat Company,

Cambridge,

Mass., a corporation of Massachusetts Application June 17, 1930, Serial No. 461,803

2 Claim.

This invention relates to gas burner systems, and with regard to certain more specific features, to gas burner systems embodying a safety device 5 for preventing the leakage of unburned gas from the system.

Among the several objects of the invention may be noted the provision of a system of the class described embodying a pilot burner and a thermostat controlled by the heat of said pilot burner, the thermostat functioning to cut off entirely the flow of gas through the system upon extinguishing of the pilot burner; a system of the class described embodying means for supplying gas to said pilot burner, upon the initial ignition thereof, at a greater-than-normal rate, whereby more quickly to heat the thermostat to move to its hot position; and the provision of a system of the class described which is relatively simple in construction and in operation. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction. and arrangements of parts which will be exemplified in the structure hereinafter described. and the scope of the application of which will be indicated in the following claims.

The accompanying drawing is alongitudinal section through a burner system embodying the present invention.

In gas burner systems, particularly such as household cooking ranges, water heaters, and the like, there is usually provided a pilot burner which remains ignited at all times and which is positioned to ignite the main burner or burners when their respective valves are opened. Due to draughts, gas-line pressure variations, and like causes, the presumably continuously ignited pilot burner is frequently extinguished. Then not only does the unignited gas flow of the pilot burner escape into the surroundings, but should a main burner valve be opened, the main burner will remain unignited and the relatively larger flow of gas therefrom also escapes unignited into the surroundings. This escape of unignited gas is of course highly undesirable.

In the present invention. by thermostatic means, extinguishing of the pilot burner instantaneously results in the closing of a main control valve whereby any and all further flow of gas in the system, either to the pilot burner or to the main burners, is positively prevented until deliberate attention has been given to the system and the pilot burner has been reignited.

Thus is gas leakage prevented with an unusually high degree of safety.

A further advantage of the system is that means are provided whereby, upon the reignition of an extinguished pilot burner, the rate of flow of gas to said pilot burner is initially increased, the more quickly to carry the thermostatic system into its hot, gas-flow sustaining, position. As soon as the thermostatic system has reached its hot position, the flow of gas to the pilot miner .is automatically restricted to a normal ra e.

Referring more particularly to the embodiment of the invention shown in the drawings, there is provided valve casing 10 which is divided into gas entrance and exit compartments 17 and 18 by a dividing partition 19, the partition 19 having a relatively large valve seat or port 20 therethrough which is controlled by valve closure member 22 which is adapted to close the port 20 gas tight. Secured to one side of the valve member 22 is a shaft or stem 23 guided through a cap 24 which is conveniently removably secured to the casing 10, as by threading therein, the removable feature of the cap permitting access to the interior of the valve casing, if needed, and the threading being readily adapted to form a gas tight joint to prevent leakage. Secured in a similar manner to the cap 24 is a cap 25 servingto protect the end of the cap 24, and holding a washer 26 in position around the stem 23 and between the end of the cap 24 and the cap 25 to substantially prevent gas leakage between these respective members. Around the stem 23 is placed a coil spring 2'? bearing against the valve member 22 and the cap 24 to seat the valve on the port 20. The valve stem 23 terminates in a handle 28 for manual grasping to open the valve as hereinafter explained.

The casing 10 is formed with a boss 29 into which is inserted a pipe 30 which leads gas from the supply line 11 to the pilot 13 by way of the passage 33. The pipe 30 is cut off from communication with the interior 18 of the casing by suitable means, such, for instance, as oil rings 31 having an oil seal between them. A rod 32, secured to the valve member 22 is passed through the pipe 30 forming an annular passage between the rod and pipe, the boss 29 having a small passageway 33 communicating between exit chamber 18 and the passage between the pipe and rod, so that, in operation, gas may pass from the casing 10 into the pipe 30 as long as the valve member 22 is not Seated. The amount of gas passing through the r! In passage 33 is controlled as desired, by any convenient means, as for example, the screw 34.

The tube 30 is fitted into the tubular member 35. This member 35 is closed by the plug 36 having a recess therein which serves as a guide for the end of rod 32, and is also provided with a lateral extension boss 37 into which is fitted member 38. Member 38 is provided with a passage or port 39 and a small by-pass 40 controlle by a screw or equivalent member 41.

Carried by the member 38 is a housing 42 in which is contained the thermostatic member 43. A rod 44 is secured to the thermostat 43 and carries a valve closure element 45 adapted to seat upon and close in gas-tight manner the port 39.

Secured to the top of housing 42 is a. member 46 to which the pilot burner 13 is attached, it being noted that the thermostat 43 is in heat conducting relation with the pilot burner 13, heat from the pilot flame operating the thermostat. Operation of the thermostat pulls the rod 44 out of its seat or groove 60 at the end of the rod 32, the seat 60 being formed by cutting away a portion or the rod adjacent its end to such depth and width that the rod 44 will readily seat within the resulting groove. This groove extends around the rod so that the rod 44 will seat within the groove in any position which the rod 32 may be turned, rod 44 serving as a latching member to prevent longitudinal movement of the rod while the burner is lighted.

It will be understood that when the burner 13 is not lighted, rod 44 is out of engagement with rod 32 and the valve 22 is seated against the port 21 under the action of the spring 27 to stop the flow of gas which is normally passing in the direction of the arrows, so that no gas can pass into any part of the gas system. In this condition the valve 45 is unseated to open the passage 38 to the burner 13. The thermostat 43 is provided with holes 61 through which gas may pass.

To light the burner, handle 28 is manually pulled outwardly so that the valve member 22 is unseated. This permits the gas to flow through the port 20, and through the by-pass 33 into the pipe 30, thence through the passage 39, thermostat 43, and is burned at the orifice of the burner 13. It will be seen that the passage 39 is relatively large in area so that a large amount of gas will pass therethrough to be burned with a large flame at the orifice. The heat from this flame is conducted to the thermostat 43, which, when it reaches its operating temperature, will take the position shown in Figure 2, thus seating the valve member 45 over the passage 38 and also holding the rod 32 by placing the stem 44 into the cutaway portion 60 of this rod. The seating of this valve 45, cuts off the large flow of gas to the burner used for pre-heating the thermostat 43, and the smaller amount of gas flowing through passage 40 reduces the pilot flame to its normal operating size. This diminution in the flame will indicate to the operate-r that the valve 22 is locked in open position and he may release his hold on the handle 28. The valve 22 is thus held in open position, the pilot flame being supplied with gas passing through the by-pass 40. This flow can be regulated as desired by operation of the screw 41.

If the pilot flame becomes extinguished the thermostat 43 cools to its operating temperature and resumes its cold position as shown by the dotted lines. This withdraws the stem 44 from its engagement with the rod 32, and permits the seating of the valve member 22 because oi the pressure of the spring 27. This cooling upon extinguishing of the pilot flame is accelerated by the circulation of gas through'the thermostat 43 between the time of the extinguishing of the flame and the time when the thermostat,acts to close the flow of gas through the line to the burner. It will be understood, however, that this. time interval is such that no substantial amount of gas flows prior to the operation of the thermostat. It is clear in this connection that the provision of a snap-acting thermostat is of value in that substantially no gas is permitted to escape while the valve 45 is opening. The quicker the thermostat acts the greater will be the safety factor in this invention.

This thermostat 43 may be of any type, but is preferably of the snap-acting, dished composite metallic disc type described and claimed in my prior United States Patent 1,448,240, issued March 13, 1923.

In view of the above, it will be seen that'the several objects of the invention are achieved and other advantageous results attained;

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a gas burner system, a main gas supply line, a spring-closed main valve therein, said main valve being operable completely to cut oil flow of gas through said main supply line, a. pilot burner, a pilot burner gas supply line connected to the delivery side of said main valve, a pilot valve in said pilot supply line, and a by-pass around said pilot valve, whereby said pilot valve is operable to throttle, but not completely to cut off, flow of gas to said pilotburner, a thermostat having a plurality of operative positions, said thermostat being located in heating relation to said pilot burner,

and means operatively connecting said thermostat to said main valve and to said pilot valve, said thermostat being operable through said means to hold said main valve open against the action of its spring, and to hold said pilot valve closed, when in its hot position, and to permit said main valve to close under the action of its spring, and to open said pilot valve, when in its cold position.

2. In a gas burner system, a main gas supply line, a main valve having a closure element and a seat therein, said closure element having a shaft extending beyond said main valve, spring means normally urging said closure element into seated relation with said valve seat; a pilot burner, a pilot burner housing, and a pilot burner gas supply line connected to the delivery side of said main valve, a pilot valve coaxial with said pilot burner, and in said pilot supply line, and a by-pass around said pilot valve of relatively restricted capacity; a snap-acting, dished composite metallic thermostatic disc, means forming part of said pilot burner housing and mounting said disc at its periphery, coaxially with said pilot burner, and in heating relation to said pilot burner, said disc having positions of opposite concavity determined by its temperature, and a rod mounted for axial movement attached to the central, movable portion of said disc; said rod carrying, intermediate its ends, the closure element of said pilot valve whereby said pilot valve is closed when said thermostat is in hot position, forcing gas to flow through said by-pass, and said pilot valve is open when said thermostat is in cold position; the said main valve shaft being positioned at right-angles to said rod and having a groove therearound, said groove being positioned to be engaged by the free end of said rod, whereby when said thermostat is in hot position, said rod end engages said groove to lock said shaft against axial movement thereby holding said main valve open, butwhen said thermostat is in cold position, said rod is removed from said groove to permit said spring means to seat said main valve.

JOHN A. SPENCER. 

